High-added-value compounds recovery from supercritical fluid extraction-defatted European sea bass (Dicentrarchus labrax) viscera by lactic acid bacteria (L. plantarum and L. casei) assisted fermentation

In this study, supercritical-CO2 (25.0 MPa, 40 degrees C, 75 min, 10.0 mL/min) was used to defeat sea bass viscera to facilitate the fermentation process. Then, the defatted samples were used as raw material to be fermented by lactic acid bacteria (Lactobacillus plantarum and Lactobacillus casei) over 72 h. After fermentation, solid matrices and supernatants were separated by centrifugation and analyzed for protein content, bioactive peptides, and minerals. Both LAB strains significantly (P < 0.05) increased protein content (24.9 % and 27.4 %) in the supernatants. Six bioactive peptides were identified, demonstrating antioxidants, anti-inflammatory, anticancer, antithrombotic, immunomodulatory, and hypolipidemic properties. Some 28 antioxidant peptide sequences were found, especially for EL (glutamic acid-phenylalanine) and KD (lysine-aspartic acid). Moreover, the mineral results showed the possibility of mineral accessibility, while the LAB strains also notably enhanced the antioxidants of the supernatants. This study highlights the potential of fish side streams in generating bioactive compounds through fermentation.